This invention relates to electric switching installations in general and more particularly to an improved explosion-proof switching installation.
A switching installation of explosion-proof design with a bus bar duct on the input side and control devices mounted in housings, of the German protection class "Explosion Proof Enclosure" known as (Sch)d, where explosion-proof contact elements are arranged between the (Sch)d housings and the bus bar duct, is described, for instance, in French Pat. No. 1,167,635. The switching devices contained in the explosion-proof housings are connected to the bus bar conductors located in the bus bar duct by disconnect switches which are designed as explosion-proof feedthroughs. In the disconnected position, a grounding contact is in effect at the same time. While this switching installation is intended for medium voltage (for instance, 3 or 4 kV), a bus bar duct located above has likewise been provided in a similar manner for several explosion-proof housings with low-voltage switching devices mounted side by side (British Pat. No. 1,171,355).
It is an object of the present invention to make a switching installation of the above-mentioned type more flexible by permitting explosion-proof housings equipped with switching devices to be added or removed without extensive installation work, if required.